About the Assessment: Participation Rates

The schools and students participating in NAEP assessments are selected to be representative of all schools nationally and of public schools at the state level. Samples of schools and students are drawn from each state and from the District of Columbia and Department of Defense schools. Because each school that participated in the assessment, and each student assessed, represents a portion of the population of interest, the results are weighted to account for the disproportionate representation of the selected sample. Read more technical information about weighting adjustments made at the school and student level.

National participation

To ensure unbiased samples, NAEP requires that participation rates for original school samples be 70 percent or higher to report national results separately for public and private schools. In instances where participation rates meet the 70 percent criteria but fall below 85 percent, a nonresponse bias analysis is conducted to determine if the responding school sample is not representative of the population, thereby introducing the potential for nonresponse bias.

Before substituting new schools for originally sampled schools that declined to participate, the student-weighted national school participation rates for the 2009 reading assessment were 97 percent for grade 4 (100 percent for public schools and 73 percent for private schools), 97 percent for grade 8 (100 percent for public schools and 72 percent for private schools), and 83 percent for grade 12 (86 percent for public schools and 52 percent for private schools). Weighted student participation rates were 95 percent at grade 4, 93 percent at grade 8, and 81 percent at grade 12. The nonresponse bias analysis for private schools at grades 4 and 8 showed that, while the original responding school sample may not have been fully representative, the potential bias was reduced by including substitute schools and by adjusting the sampling weights to account for school nonresponse. At grade 12, the school participation rate for private schools fell below the standard for reporting.

Because the grade 12 weighted student participation rate in public schools was below 85 percent (80 percent), a student nonresponse bias analysis was conducted. That analysis showed that the responding student sample differed from the original student sample with respect to race, relative age, and student disability status. After adjusting the sampling weights to account for student nonresponse, the remaining bias was small, with the nonresponse adjusted estimates for the three identified variables differing from the unadjusted estimates by plus or minus 0.1 percentage points.

State and district participation

Standards established by the National Assessment Governing Board require that school participation rates for the original state samples need to be at least 85 percent for results to be reported. In 2009, all 52 states and jurisdictions, along with all 18 districts participating in the reading assessment at grades 4 and 8 met this participation rate requirement. Because the weighted school participation rate in Illinois was 84.5 percent, a school nonresponse bias analysis was conducted for the grade 12 public school sample in that state. That analysis showed that the potential nonresponse bias was effectively reduced by including substitute schools and adjusting the sampling weights to account for school nonresponse. The school participation rates for the remaining 10 states all met the required standard with weighted participation rates ranging from 92 to 100 percent.

Student nonresponse bias analyses were conducted at grade 12 for Connecticut, Florida, Illinois, Iowa, Massachusetts, New Hampshire, New Jersey, South Dakota, and West Virginia, where the student response rate fell below 85 percent. Across these nine states, after nonresponse adjustments, the percentage difference between nonresponse adjusted sample and eligible student sample was 1.3 percent or less. Based on the student characteristics available, there does not appear to be evidence of substantial bias resulting from student nonresponse.

The tables below provide participation rates before substitution.

Learn more about the sampling design.

School and student participation rates in NAEP reading at grade 8, by state/jurisdiction: 2009
State/jurisdiction	Student- weighted percent	School- weighted percent	Number of schools participating	Student- weighted percent	Number of students assessed
	School participation			Student participation
Nation	97	87	7,030	93	160,900
Public	100	100	6,510	92	155,400
Private	72	68	360	95	3,100
Alabama	100	100	110	93	2,700
Alaska	98	88	100	91	2,500
Arizona	100	100	130	92	2,800
Arkansas	100	100	120	93	2,700
California	100	100	230	92	7,200
Colorado	100	100	120	93	2,800
Connecticut	100	100	110	92	2,800
Delaware	100	100	50	92	2,800
Florida	100	100	160	91	4,200
Georgia	100	100	120	93	3,500
Hawaii	100	100	70	92	2,900
Idaho	100	100	110	94	3,000
Illinois	100	100	200	94	4,100
Indiana	100	100	110	93	2,700
Iowa	100	100	130	94	2,600
Kansas	99	99	120	95	2,700
Kentucky	100	100	130	94	3,500
Louisiana	100	100	120	93	2,600
Maine	100	100	140	93	2,700
Maryland	100	100	130	92	3,200
Massachusetts	100	100	140	92	3,600
Michigan	100	100	150	92	3,300
Minnesota	100	100	140	92	2,900
Mississippi	100	100	120	94	2,800
Missouri	100	100	130	94	2,700
Montana	100	98	170	91	2,600
Nebraska	100	100	120	95	2,600
Nevada	100	100	90	92	2,900
New Hampshire	96	96	90	90	2,500
New Jersey	100	100	110	93	2,700
New Mexico	100	100	100	90	2,500
New York	97	98	150	90	3,700
North Carolina	100	100	150	92	4,500
North Dakota	100	100	180	95	2,100
Ohio	100	100	190	93	3,400
Oklahoma	100	100	150	93	2,700
Oregon	100	100	130	92	2,900
Pennsylvania	100	100	150	92	3,500
Rhode Island	100	100	60	92	2,700
South Carolina	100	100	110	93	2,700
South Dakota	100	100	220	95	2,800
Tennessee	100	100	120	93	2,800
Texas	99	100	170	92	5,700
Utah	100	100	110	91	2,800
Vermont	100	100	120	93	2,900
Virginia	100	100	110	93	2,800
Washington	100	100	130	91	2,800
West Virginia	100	100	120	92	2,900
Wisconsin	99	99	170	93	3,400
Wyoming	100	100	90	91	1,900
Other jurisdictions
BIE¹	80	83	90	89	800
District of Columbia	100	100	60	89	1,600
DoDEA²	99	97	60	93	1,600
¹ Bureau of Indian Education. ² Department of Defense Education Activity (overseas and domestic schools). NOTE: The number of schools is rounded to the nearest ten. The number of students is rounded to the nearest hundred. The national totals for schools include Department of Defense Education Activity (overseas and domestic schools) and Bureau of Indian Education schools, which are not included in either the public or private totals. The national totals for students include students in these schools. Columns of percentages have different denominators. Detail may not sum to totals because of rounding. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2009 Reading Assessment.